You don't have to make a new being, God is in control of the whole universe! There are a couple of ways I've seen this handled. The first is what C.S. Lewis did in his space trilogy, where he gave each planet its own Creation, and possibility of a fall. But it turned out that only earth succumbed to the temptation. So, you could have something like that. Also, Stephen Lawhead has written a few sci-fi books, and each of them has God in it without making it a huge deal. Aliens don't have to be the same as us, the martians in Lawhead's Dreamthief know God and either live in harmony with him or are evil. In the Empyrion Saga Lawhead explores redemption in a very real way with one of his characters, and the aliens already know God and that is where the MC actually learns about Him. All that to say, you have options, If you go for straight allegory like Lewis or if you are just trying to put God in your writing (which is a very good idea
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. I'm focusing on a short story at the moment.